The Strongest Villain
by AngelicIncubus
Summary: "Don't you think that punch was... a bit light, Saitama the hero?"
1. Chapter 1

**Chapter 1: Like Looking In A Mirror**

"Don't you think that punch was… a bit light, Saitama the hero?"

"Huh?" Saitama was perplexed. He had just punched this Boros guy into one of the structures supporting his ship, partly because he had said he went around killing off whole civilizations because of boredom, and partly because he had reminded Saitama of those darn telemarketers. But something was a bit strange.

"Oh, you can keep going?" Saitama had never encountered an enemy that had even survived one of his casual punches, much less could keep going no worse for the wear. "You're a lot stronger than you look at first glance, and definitely stronger than the other freaks around here."

"That punch was but a miniscule fraction of the power you possess. I am not so easily done in, Saitama the hero," Boros said matter of factly. The alien intruder was getting excited, even though he could tell that punch was massively weak compared to what the hero could put out, it had sent him flying, yet it did not break his armor.

Now Saitama definitely knew something was up. No one was privy to the fact that he held back in his fights hitherto, and this guy didn't look the least bit intimidated that a casual punch had sent him flying. He was wearing armor, so Saitama guessed that it had done a really good job of soaking up the impact. Yet, still, this sense of _foreboding_ was a strange feeling. There wasn't a single entity alive that could outright scare him (or cause him to feel much emotion at all even), but this Boros guy was definitely a step above anything he had faced up until this point. Stranger still, he felt a sort of… companionship.

"Before we begin, I will explain some things to you, Saitama. This armor restricts my power, you see. Should it break, this world will come to an end unless you are the foe in the prophecy."

"Prophecy? You mean…" Saitama was mildly intrigued. What was this "prophecy" he spoke of?

The alien cyclops began speaking once again. "You see, I am simply too strong. For 20 years, I have wandered the galaxy in search of foes that would re-ignite my passion for battle, but none so far have proved worthy. _You_ , on the other hand, have managed to make me excited at the prospect of fighting once more. Though I have not felt the same passion as decades ago, I feel that you will be-"

"20 WORDS OR LESS!" Saitama shouted out abruptly. The hero was never one for deep villain monologues, it was the very reason he couldn't even fathom facing someone like Sosuke Aizen from that Bleach manga he had read a few years ago. Boy does that dude talk a lot, everything is always "according to plan" with that douche.

Boros, having never met someone quite so brash in the face of an opponent, acquiesced nonetheless. "We will fight, and that is all." With a smirk that most of his crewman aboard his ship thought him incapable of making, Boros moved at speeds incomprehensible to the human eye… Well, a _normal_ human's eyes anyway. Saitama had no difficulty tracking him. Appearing behind the hero, Boros slammed his fist into him, and noticed that Saitama didn't even bother to block his punch, taking it head on without so much as fidgeting a bit.

"Good, good. You are at least this sturdy, this should be fun!" Despite wearing such heavy-set armor, Boros was faster than most beings could perceive. Saitama thought this impressive, but it still did not satisfy him like the prophecy spoke of. Although, he was the slightest bit intrigued that this Boros character felt the need to hold back against him at all. Deciding to test him, he issued a simple counter-strike. Cranking his speed up slightly to the levels that Boros had just shown he could go on, Saitama maneuvered behind him and struck him dead on with a _slightly_ more powerful punch, so as not to completely obliterate him (or so he thought).

"… It seems you won't take this seriously until I do, Saitama the hero. Well, if that's the case, how about we take the kiddy gloves off for a bit?" Boros was unmoved by the punch! This guy was much more powerful than any other enemy, extremely so in fact. Boasting a maniacal smile that only a true battle-maniac could, Boros elbowed Saitama and sent him flying through three pillars.

"Isn't this fun!?" The mad cyclops ran at Saitama, who had crashed into a final pillar. Breaking through the ones that Saitama had crashed through, Boros delivered a dropkick to the strongest hero and caused the pillar they were on to explode. However, they outsped the explosion with their immense speed, circling up the pillar to the top of Boros' ship. Boros was on the offensive, while Saitama simply dodged all hits. Going through the material of the ship, they came up in a chunk of it (still fighting and causing dents in it) before eventually splitting apart a few meters away from each other.

"He got my costume dirty, that sucks." Saitama, a bit peeved that Boros had gotten his costume dirty after he just recently washed it, reprimanded him.

"Dude, I know that you're the denominator of the universe or whatever, but you could **PLEASE** not throw dust particles everywhere you…" his rant was cut off by a knee to the face, followed by a 4 punch combo that ended in an uppercut. Saitama, battle instincts kicking in, immediately recovered and delivered a counter-strike.

"Normal Consecutive Punches" the hero said nonchalantly after landing and blitzing the alien cyclops who just interrupted him. With that, it happened. Boros armor broke, causing the alien to reflect on the situation at hand.

"This set of armor, used to seal in my immeasurable, irresistible power, has been broken." Saitama's response?

"Ok (._.)" The hero's face resembled that of a man who had just found out that his wife was cheating on him, but he was cheating on her as well. Thinking back a bit though, Saitama remembered that this guy had actually blitzed him before he finished his request. More so than it being rude, Saitama was actually caught off-guard by the speed of the alien, something not even an amped up Genos or Lump O' Coal Tonic (?) could do.

"You're pretty strong." Saitama actually felt a twinge of happiness, maybe this guy _would_ be able to slightly challenge him, or as the alien cyclops might put it, "give stimulation" to his existence. Still feeling the need to tell him off, however, he started reprimanding again.

"Hey, you know it's pretty rude to interrupt somebody don't you?" H not only stood for hero, but for hypocrite as well in Saitama's case.

Boros, having finished off the transformation he was going through while Saitama was internally mulling things over, started to emit copious amounts of latent energy and responded in kind. What could this being, seemingly a match for Saitama's lesser focus, possibly say in retort to the hero's allegations?

"Well, it wasn't 20 words or less, you see." Saitama didn't know whether the alien was mocking him or actually took on his dislike of long-winded rants, but his face didn't share the same confusion. The shine on his bald head did a lap over it, before his face (now twisted into one of despair) pans back into view. This alien reminded him of Tatsumaki, and that actually put him in a bad mood (Tatsumaki and Genos were the only individuals so far who made him feel any type of emotion, and it's safe to say that Tornado's constant insults and snarks didn't incite happiness and rainbows within him).

"Wait. An opponent? An _actual_ opponent made me feel something?"


	2. Chapter 2

**Chapter 2: Immovable Object Vs Irresistible Force**

Saitama is currently laying on the ground with a blank expression. This Boros guy had blitzed him _again_ and actually managed to knock him off his feet when he was slightly focused. Contemplating, Saitama sat up only to be greeted by Boros' unnerving visage (unnerving to everyone except Saitama of course, who just deadpanned).

"You're hardly fighting back. Come on, make this fun for me, Saitama the hero." He wasn't wrong, Saitama hadn't thrown a punch since he broke the alien guy's armor. Boros, sensing this, started to elaborate.

"If you are indeed the opponent of prophecy, then you need not worry about holding back your strength. My armor was merely a power limiter, it offered me no protection beyond what I already naturally have."

"Huh, nice to know." Saitama didn't care one way or the other about Boros' pleasantries, but he did feel a sensation welling up in him. Seeing as how his opponent was clearly a capable combatant, he'd ramp his power up to about 15% of it's max output and funnel the force behind his strike into a singular, linear path. That way, the city wouldn't be destroyed, and he'd most likely be able to take this guy out.

"Thanks for the reassurance, but I'm not worried about a thing." Launching himself upward from the ground after saying that, Saitama threw a feint punch. Boros didn't seem to bite on it, maybe he saw through it, or maybe he simply didn't care to block it. This struck Saitama as odd, but he carried through with his feint nonetheless, turning the straight right into a lefty backhand. It made contact unimpeded with Boros' face, the force behind it causing a massive amount of air to be displaced and the parts of the ship directly behind Boros to be obliterated.

"You're determined to test me, aren't you, hero? Very well, I will demonstrate my power for you as you have for me." Saitama was then swiftly decked in the face, sending him flying upwards. Boros outsped his upwards motion into the air and turned around, sending him back down to the ground with a double ax handle. Now somehow floating, his body began to discharge it's latent energy in the form of electricity. His hair stood up and became even spikier, similar to a super saiyan 2 transformation from "DBZ."

"This prophecy may yet be true. Out of all the myriad beings I have faced so far, only **YOU** have lasted this long!" Grinning like the maniac he is, Boros discharged a beam from an eye that resided on his chest. Saitama, now laying on the ground again face-up, actually cracked a small smile. This guy was no pushover, and required actual effort on his part. He had no way of knowing just how hard the guy was trying, but he figured it wouldn't matter in the end if he got the fight he wanted from this so-called "prophecy."

The beam collided with Saitama and went straight through the ship down to the level where his subordinate, Melzalgald, had been dispatched (accordingly, also the level where the other S-class heroes were fighting). Saitama was sent directly into the underground, but leapt back up with such speeds that no one at the lower level of fighting saw him. Upon arriving back at the top of this ship, his clothing was partially evaporated and he had an amused expression on his face. Since it'd be a pain to draw out the fight after all, he decided he'd just straight up ask the guy how hard he was trying.

"Hey, Burrito or whatever, how much power are you using… percentage-wise?" Saitama's lack of manners and general short-term memory was as much a sight to behold as his immense strength.

"Since you have done so well, I will answer your query, hero." Boros, disregarding Saitama's lack of manners (it's a battle to the death, and Boros knew that there wasn't any space for formalities when you were trying to kill each other anyway), gave an answer that caused Saitama's smile to widen slightly.

"If I had to give it a label, I'd say around 20%. You haven't bared your fangs even once, so I will respond in kind." He didn't seem like he was lying, so Saitama accepted his answer. There wasn't any wear and tear from any of their previous spats in this fight, and the guy could take a punch (pun intended). Saitama, mind ablaze at the prospect of being only about 5% stronger than someone, got into a stance for the first time in his hero career.

"Oh, finally decided to fight back have we?" Boros singular eye widened and became bloodshot, he sported his signature grin with sharp teeth. His probable prophesied rival may be about to show his true colors.

"Yeah, I might even need to get a little _serious."_

 **-Destroyed Ship Interior-**

"This place certainly is freaky looking, where'd they get their sense of decoration, a Star Wars thrift shop?" Tatsumaki was currently aboard the ship that Saitama had just passed through. She, like the other heroes present, stopped her current activities when a large, blue blast suddenly erupted from the ship's interior and made a large hole in the ground. Being the only hero who could fly (and the only one not pre-occupied with fighting or standing by idly) she levitated up through the hole made in the ship without any of the other heroes noticing.

"Why the hell is this place so large!? It's like a freaking mall for weirdos!" Tatsumaki's rage flared up. She thought about just turning back or bisecting the whole damn thing with her psychic powers, but stopped when she realized something. The place was already heavily damaged. The recent beam could have contributed to some of the destruction, but something wasn't right. If the beam was the sole cause, it would have completely obliterated whatever was in it's path, as beams tend to do. Some things aboard the ship were still intact, just barely, but still there. That meant something else had to have happened, maybe some sort of battle took place. If that was the case, someone from the heroes side had to have boarded the ship already. Who could've slipped away like that (not counting herself, of course)?

Tatsumaki stalked about until she felt two extremely large waves of latent energy coming from directly on top of her. She was in what she presumed to be the throne room, as, well, there was a throne with a large, almost crystal-like structure behind it. Making a mental note to come back and destroy the important looking structure later, she followed the two energy sources (and the destruction they wrought) all the way up to a hole that was seemingly blown through the roof of the ship. Emerging cautiously, the two waves of energy hit her like a truck.

 **-Ship Surface, Tatsumaki's Perspective-**

Disoriented, but not unconscious, Tatsumaki turned in the direction of the two extremely powerful energy sources. Exceptionally powerful energy waves overloaded her senses and caused a major headache, but she could still operate fairly normally, usually. This time, though, she was _reeling._ Never before had she felt such power, such ferocity and not even seen who it was emanating from. Trying to make sense of it all, shekept her eyes peeled for any signs of the two life-forms giving off these, these… _godly_ energy outputs.

Suddenly, two blows passed by her field of view. The ship's many structures were melting on contact with the blurs, and their energy outputs flared every-time they clashed. After about 5 clashes, the blurs separated into two inividuals at a medium distance away from her. The first one was the leader of the ship she presumed, as he gave off one half of the massive energy output and was clearly not an inhabitant of this planet with his stature and perpetually glowing body. The second… the second was someone a bit familiar. Bald head, white cape, red boots and gloves…

"THE B-CLASS!?"


	3. Chapter 3

**Chapter 3: This Is My Fight**

Tatsumaki was in utter disbelief at the situation. Maybe it was the nausea from the sheer power the two in front of her were putting out, or the explosions they were causing on this ship that blocked out the sun from below, but she just couldn't stomach what was happening.

"How… how could this B-class even still be alive? He CAN'T be that powerful… can he?" Thinking back, Tatsumaki tried to remember his name, but was drawing a blank. So, she settled for simply calling him caped baldy in her theories. As much as it irked her to have do think about things like this, she couldn't deny what was right in front of her, that wasn't her style no matter how stubborn of a front she'd usually put up. Still disoriented from the power surge, she simply decided to lay low and ponder. Jumping into the fight now would only hinder both her and caped baldy, seeing as how she was nauseated beyond belief.

"… You'd better win, cueball." As she said that, she couldn't help but feel a bit embarrassed. She had never relied on anyone in her entire life to win a fight, mostly because she was powerful enough to do it on her own 99% of the time and partly because she just didn't like to admit to needing help. _This_ time however, she felt a feeling she hadn't felt in a very long time: trust. Why, she honestly didn't know, but it was that inkling of trust she had in the caped baldy that narrowly convinced her to swallow her pride and see what happens, and so, that's what she'll do.

( _Back to the fight)_

"This guy seriously has my hopes up." Saitama was ecstatic, as he traded blows with Boros. The sensation, the _thrill_ of actually being susceptible to defeat was driving him to fight in a manner that he'd never even dreamed he'd be able to. While still nowhere near his upper limit of strength, his hits boasted more force, more savagery, more reckless abandon than even when he first started out. After circling around in the air and colliding fists with Boros, the two were blown back to their previous standing positions. Boros was notably marked with bruises, but his maniacal smile was as healthy as ever.

"I haven't been bruised in ages. I can sense no limit to your strength." Boros' compliment was one that felt empty to Saitama, however. Normally a villain would panic had they suffered as many blows as hard as he did, but his composure has been regal since the fight began.

"But there's a catch, isn't there? You've been holding back this entire time, don't tell me a few bruises was all it took to impress you." Saitama was seriously hoping for more, as he didn't want the fight to end _just yet_. He'd get his wish.

"A perceptive warrior indeed, I was right to invade this planet." Boros, seeing the focus on Saitama's face, decided to show him what he meant by this offhanded statement. His body's perpetual glowed brightened, and after the light settled down, his bruises were gone. It's as if they had never existed in the first place.

"Good as new. You, on the other hand, will only continue to be injured, unless you come at me with your **full** power, Saitama."

It didn't take a wise guy to realize the gravity of the situation. Saitama was currently at about 17% full strength, which was the max he could put forth without completely decimating a city with every blow. A fraction more, and he'd have to take the fight out of the area to preserve whatever was left of City A and the other cities as well (as much as he enjoyed the fight, complete destruction couldn't just be written off as a side-effect, he is a _hero-for-fun_ after all).

"You know, this entire ship could be destroyed if we don't hold back?" said the hero. Saitama didn't care in the slightest for the wellbeing of the ship, he just figured he'd try something before resulting to brute force and having to take the fight elsewhere.

Just as his words finished, the ship was cut in half by an enormous trail of energy. Boros had simply disregarded the advice and moved faster than the speed of sound, creating a sonic boom in the process and igniting the path he tread on right down the middle of the ship.

"Ships can be replicated. This fight, however, **can not**." His words oozed with enthusiasm as did the blow that struck Saitama's guard. "I don't plan on destroying this planet just yet, as long as there are sections of it left, we can fight to our heart's content." The madman's smile would not cease.

The force from the blow was so strong, the half of the ship they were standing on evaporated, leaving them in the air for all to see, especially one ESPer…

 **-Bisected Ship Half, Tatsumaki's POV-**

"WHAT THE HELL IS GOING ON!? I look away for 5 seconds to take a deep breath, and I'm free-falling! What did that B-class do!?" Tatsumaki was currently plummeting to the ground with the still-intact half of the ship. The two energy outputs were far away enough so that she didn't feel heavily nauseous anymore, so she tried to regain her focus and fly.

"This is so much harder than it should be, aww geez!" Wobbling in the air, she emitted a green aura and corrected her form. Now standing upright with a slightly annoyed look on her face, she floated at the precise position she had gained control over her powers again. Looking down on the combatants she had left behind, she came to a realization.

"Oh shit… **I** might not be falling, but the **ship** still is…" Not one to have to deal with the press about "unnecessary deaths", she quickly dive-bombed in an effort to catch up to the ship and stop it's momentum. Upon arriving within a few meters of the structure, she stretched out her hand and a green aura enveloped the ship, slowing it's fall.

"It's still going too fast! Ugh!" Annoyed by the fact that she'd have to put extra effort in, she held out her previously free hand and concentrated harder. Lifting an object of such mass required a lot of energy, whether it be physically or by telekenesis, and Tatsumaki had never bothered to lift such a mass before while under debilitating conditions (the nausea was reduced in effect, but it hadn't gone away altogether). Straining to keep the ship at a stand-still, she shouted her grievances at the individuals below, who did in fact notice the moment that the ship had been partially evaporated.

"It's not like I'm doing this for you weaklings or anything! Hmph!"

 **-Genos POV-**

The cyborg had only been standing idly by, though he was the first to notice that the ship was cut in half due to his robotic makeup enhancing each of his senses. Upon seeing the massive underside of the remaining ship-half coated in a green aura, he assumed that either sensei or Tatsumaki had bisected it, which one he didn't really care. He thought about leaving, since his master had _surely_ dispatched of the ship's leader by now, and there was no need to stay. Just then, though, he noticed it…

"Wait… the ship's still moving in a downward motion… at a fairly decent speed. Tornado-san must be trying to stop it from moving, judging by the green glow." Genos scouted out the situation. Normally, Tatsumaki would've thrown the large object into space by now. _Something_ must be inhibiting her, but Genos couldn't do anything about it. His firepower _could_ only cause Tornado's ordeal to worsen, and the intense heat could potentially loosen Tornado's grip on the vessel. None of the other heroes present specialized in stopping objects of such size, and they all just plain lacked the firepower even if they did it would seem.

"Tch. I'll just have to rely on sensei if push comes to shove. I despise being powerless."

( _back to the fight)_

The two powerhouses were uninterrupted in their fight. Apparently, no one (save for Tatsumaki) had seen them, instead focusing on the crashing ship. They traded fists and dodged some blows as well, cutting through the air with each strike.

"Do you ever get tired of smiling!?" Saitama was genuinely a little creeped out by the smile that Boros wore on his face in every situation. His ex-girlfriend had a smile that wouldn't go away either, and there's a very obvious reason she's an ex if you read into that statement.

"I've traveled for years to arrive here. This battle is the one that will sate my desire for a challenge, I am sure of it." Not directly answering the question, Boros continued to mount his offensive attack.

"Geez, I guess I have do have to take this out of the city, but how on such short notice?" Saitama got deep into his thoughts as he dodged a knee from Boros. Truthfully, he wanted the fight to go on too, but changing locations and the persistence of the crazy smile lessened the sensations of the moment (albeit only slightly, there was nothing that would completely ruin Saitama's fated battle outside of the complete destruction of earth and his favorite supermarket).

Suddenly, Boros stopped his onslaught. His smile faded, and his face became a deadpan much like Saitama's default look. Something was wrong.

"There is a bug sharing our airspace. I can't have weaklings ruining my enjoyment, now can I?" Changing direction, Boros took off in the direction of his still remaining ship half. More specifically, he took off in the direction of Tatsumaki. His speed was inconceivable to all but his rival, and Saitama was left perplexed, until he seen Tornado.

"Geez, no one lets me do my job at all." Cranking his speed up to slightly, Saitama briefly outsped Boros and grabbed Tatsumaki before even she noticed it. Boros plunged fist-first into the ship, destroying the remaining half as well as creating a crater. He landed on the exact position where the S-class heroes were stationed, knocking everyone unconscious and inadvertently killing his own subordinate in the shockwave that came from his crash.

"That woman must mean something to Saitama. If so, I will not kill her for the time being, I will save that for after I have bested him. Maybe I'll even take her for myself, to the victor goes the spoils as they say." Boros contemplated his future victory. He didn't have any vested romantic interest in Tatsumaki, but it's only customary that the winner of such a grand bout take the hand of any maiden that was involved as well. Not only that, she had interrupted his fight merely with her presence, so payback would be issued accordingly should he ever feel the need to _let loose_. Leaping into the air, he followed Saitama's trajectory, outside of the city.

Cradled firmly into Saitama's arms, Tatsumaki was steaming red. She was seething with rage, yet she also had never been held like that before.

"WHAT ARE YOU DOING, YOU DISGUSTING B-CLASS!? Put me down right now! I'll rip off your ***** and shove it in your *** so then you'll have to **** sideways!" She shouted obscenities at him, though he ignored it and offered a simple explanation.

"Just shut up and come with me, you'll thank yourself later."

Stunned by what the situation _seemed_ to be, Tatsumaki practically blew a fuse. She had never noticed before, but now that she was up close, Saitama was remarkably chiseled under his suit. It made sense that he'd have a crush on her (after all, he is a creepy b-class that tried to get close to his superiors), but she never thought he'd act on it. Noticing how tight his grip was, she didn't know what was coming next, so she came up with an outline.

"Ok, ok… I consent. BUT, if we're gonna do this, I'll need about 20 minutes for hair, 30 for outfit choosing, and 40 for girl things, got it?"

"What the hell are you talking about?" Saitama considered just dropping her since she _can_ fly, but upon second thought, Boros was probably only about 10 seconds behind him, and he didn't want Tornado to be caught by him because of a petty squabble.

"What do you mean? You know exactly what I'm talking about. After all, you just swooped in and… carried me off."

"… Tsundere? Fuck me, I didn't think this through." Saitama's thoughts were halted as he reached his destination, an abandoned archipelago in the ocean on the opposite side of the world. Gently setting Tatsumaki down, he urged her to sit tight.

"Just wait here and don't go anywhere. I have some business to attend to."

"Where do you get off giving _me_ orders!? Remember your place, baldy! Octopus! Kneecap! Boiled Egg! Light Bulb!" Picking up a nearby stone that was approximately 3 times his size, she through it at him. Saitama stood strong, with a face that didn't show any amusement, and took the boulder head on. When the brief dust cloud settled, Tatsumaki was startled to see that Saitama had no injuries or even a scuffed up suit. Closing the small gap between them, Saitama grabbed her hand firmly.

"W-w-w-w what are you doing!? Let go!" She squirmed and wriggled violently, trying futilely to break out of his grasp. He brought her face mere inches from his, and gave her one of the sternest looks he had ever given anyone.

"Look, I'm just going to say this. This is MY fight. I don't intend on letting anyone, especially you, get in the way, you could get hurt. Understand?" Tatsumaki had never been in this type of situation before. No one, let alone a _man,_ could assert their authority over her like this. It was weird, it was inconceivable, and to her… it was oddly arousing. Turning red all over the instant she noticed what was going through her mind, she simply complied and began to wonder why she was such an idiot.

"O- ok." Her inner self was having a civil war, mostly because she misinterpreted what Saitama had meant. He wanted to fight alone, but he also cared about his friend and fellow heroes as well. Which type of "care" Tatsumaki envisioned was obvious, however.

Boros landed on the island shortly after Saitama faced away from Tatsumaki. The impact of his landing caused the foundation of the island to crack. He sparkled with what was seemingly electricity and latent energy all over ( **Goku is that you?)** , sporting his same maniacal grin of previous fame.

The two warriors stood silently for what seemed like an eternity, sizing each other up. Saitama broke the ice with a rather simple statement.

"25%?"

"30%." Boros responded.

With that, the two crushed the island they were standing on with colliding blows. Tatsumaki had come out of her stupor long enough to put up a psychic barrier, though the feeling of nausea was back from being in close proximity to those two juggernauts again.

Saitama couldn't help but crack a small, triumphant smile himself and utter a few words.

" _Serious Series time."_


	4. Chapter 4

**Chapter 4- Who's THE Strongest?**

 **-Destroyed Archipelago-**

Powerful. There wasn't any other way to describe the current fight of the two seemingly transcendent beings. It only took a few blows to completely disintegrate the islands in the archipelago, with the combatants now standing on the sole island that they designated for combat.

"The prophecy is indeed true. I acknowledge your strength, hero." Boros, the invader, was gleeful as he had finally found an opponent worth defeating.

"Same here, uhh… alien guy." Saitama's words held the same meaning, but as always, he's not one to be overly articulate when expressing it (truthfully, he had forgotten his opponents name and didn't want to bother remembering it). The lone spectator, Tatsumaki, was silent as she had to concentrate since her shields had been constantly evaporated by the power output from the two and she had to re-forge them, les she be caught in the crossfire.

It wasn't like either of the combatants wanted to _lose_ , no, far from it. What they both wanted in their own ways, was a simple thrill. A challenge that neither of them have had since they awakened to their true powers.

"There's no reason to continue on like this, whats-your-face." Saitama was the one to initiate the conversation this time. "This battle is definitely entertaining, but I don't have the kind of time to prolong it. We could fight all week, and that is NOT going to fly since there's a supermarket sale in 2 days." Saitama felt the need to rush even his destined fight, there's just absolutely no way he's missing 75% off of all udon-based products.

"Hmm, I suppose you are right. The thrill in a battle is most often felt in its waning moments, its climax." The alien cyclops agreed, though his logic was not any less wayward. He then noticed that the previous vermin he'd tried to exterminate was still there, albeit in a slightly worse state.

"Hmm. Hero, does that woman mean something to you? Is she your subordinate?" The alien cyclops felt a twinge of curiosity. He could never see those weaker than him as anything other than subordinates or boring if he was to battle them, so saving their lives was a matter not worth wasting time on.

"I guess you can say she does." Saitama responded with his usual deadpan face, not entirely understanding the context of the question. Tatsumaki somehow heard this through her concentration.

"WHAT THE HELL DOES HE MEAN BY THAT!?" The esper was thrown for a ride. Her mind started going into vicious cycles of imagination, dreaming up scenarios where he was confessing to her and the like. It was weird in every sense of the word, especially considering how she acted towards not only him but people in general, but the only thing she could seem to notice was his aura of strength in all these scenarios. No, not the bald head, plain look, or seeming inability to show emotion, but his strength. After all, with her and her sibling's past, strength was _everything_. You _had_ to recognize it, and Saitama had it in spades at the moment. "Maybe that's why I'm…" she didn't finish her sentence, even though she said it mentally.

Saitama, having left out a part from his explanation, had a light-bulb ding over his head. Oddly enough, the sun had decided to shine over the surface of his head, so it wasn't much different from the illumination of a light-bulb anyway.

"She's a fellow hero, so there's that too." Tatsumaki did not hear this in her stupor, so the misunderstanding seemed fated not to be resolved, at least for the meantime. The moment Saitama finished his sentence, though, a fist crashed into his face and sent him skidding along the surrounding water's surface. He crashed into a tree on the same island he was once standing on within a few seconds, something he noted to be impossible since he had clearly be hit away from the island, unless… he had been hit around the planet. He might as well have took a trip to the moon and back with the distance covered.

Boros had suddenly charged him, electricity spouting from his being again. When Saitama returned, he slowly walked towards him and spoke.

"I've decided, hero." His tone was authoritarian, not unlike you'd expect to hear from a dictator such as himself. "This battle will **NOT** end." Striking Saitama with a particularly powerful elbow to the face and sending tidal waves across the ocean, he waited for Saitama's response.

"Huh, why not?" The strongest hero was genuinely perplexed. "This is a Deathmatch right? One of us is eventually going to kick the bucket, ya know?" The elbow hadn't phased him, but the statement did leave a mark. For all of his downfalls in the intellectual department, Saitama knew how a fight went in this world. Kill or be killed.

Seeing his confused expression, the tyrant's smirk returned and he began to explain.

"We are the only two beings who can challenge each other, Saitama the hero. It would be a shame if I lost my only true rival, so I reached a conclusion. I will not destroy this world, on the condition that you agree to face me in battle whenever-

Saitama punched Boros in the gut.

"Are you stupid? You can't just go around slaughtering civilizations and expect people to take you seriously, add on to that you trashed A city and it's a deal-breaker." Saitama, ever the hero, simply could not let the tyrant leave the earth alive, even if he was the only rival in the entire galaxy.

Boros responded with a shot to caped baldy's kidneys.

"Weaklings mean nothing at all to me. I will spare whatever civilizations I come across in the meantime, this is the only fight I desire to participate in from now on. Your city can easily be rebuilt with my technology." Boros still managed to be prideful even during negotiations. Being as powerful as he was, it was easy to see why.

Proposition noted, Saitama kicked Boros into the air and followed suit. The bout had degraded into a simple fistfight, each person throwing blows. Boros threw a flurry of punches, with Saitama catching them all. Saitama lashed out with both his fists, using a move he hadn't used before on anyone.

"Two handed normal combo." The attack caught Boros, sending him crashing down into the ocean. Saitama didn't stop there, diving into the water and outpacing Boros fall.

"Serious Series: Serious Headbutt." Putting a good amount of effort into his move (as good as he had to anyway), Saitama headbutted Boros back into the lone island, causing it to crack.

"One more, Serious Series: Serious Elbow Drop!" Saitama plunged his elbow into the alien's chest, causing the lone island to collapse and the combatants to plunge into the water. Even Saitama couldn't keep his deadpan expression in place, smiling as he drove his elbow into Boros' body. His costume had become slightly torn from the amount of pressure exerted during their fight, and he had noticed that he was actually _bleeding_. That elbow had managed to open him up, though it's not severe. He hadn't noticed because he hadn't ever needed to pay attention to his own state since his fights were over as quickly as they began.

A green light enveloped him as he sunk, pulling him back to the surface and holding him in place. Tatsumaki had regained her composure, nausea fading away shortly before.

"You'd better thank me, B-class. Where would you be without an S-class like me to babysit you?" Her bark was still stinging, but her tone was noticeably milder. Saitama simply floated there, not really sure if he should answer or just keep his mouth shut. Women were minefields, and this one was an entire war zone onto herself.

"What is this? Why is my chest heaving up and down so weirdly?" He was right. His chest had lost its usual rhythm, taking on an erratic, staggered pattern. He was breathing _heavy_ , a sign of physical exertion (semi-heavy breathing to be exact). Saitama hadn't needed to do so outside of his dreams in a long time, so it felt weird for it to happen now, but he welcomed it. He had actually been at 50% in that short, burst-like instance just then, so it was astounding that anything was still standing. Whirlpools had formed around the spot where he sunk. Tatsumaki was nagging his ear off, but he was just in his own world.

"I know that didn't kill you… Boros. It's almost time to finish this."

 **-Deep Sea-**

"… My rival's power is incredible. I believe it is time I respond in kind."

 **-Ocean Surface-**

The ocean where Boros had sunk began to ripple violently. Saitama was the only one to notice this, as Tatsumaki had gone into overprotective wife mode and was nagging his ears off. Behind every powerful man was indeed a more powerful women, not that Saitama and Tornado were dating anyway.

Suddenly, it happened. The ocean split in two as far as the eye can see, revealing a light-purple orb on the visible ocean floor that radiated power too immense for any lower beings to stand up straight in. True to the aforementioned sentence, Tatsumaki began to feel the enormous wave of power press down on her, and descended to the now barren ocean floor, releasing her grip on Saitama as well as she couldn't withstand the strain.

Saitama now stood still, having needed no time at all to recover from his fatigue. Boros' body had changed yet again, taking on a whitish tinge with what appeared to be veins running across it. His hair elongated, going midway down his back in a wild arch. He was on one knee in a stance that seemed to indicate that he was going to take off, and Saitama knew that the end of the fight drew near. Turning to Tatsumaki, who was out of breath just being in the presence of Boros' unrestrained power, he told her what to do.

"Get out of here. NOW." His tone indicated that there was no room for arguing, but even so, Tatsumaki defied him, shouting obscenities at him absentmindedly. Seeing no merit in standing around and arguing with her, he moved silently, picking her up and flinging her over his back, an action she found herself unable to resist for various reasons, some having to do with the fact that he was simply more powerful, and some not so "safe for work"

"Oh, that's right, Japan is on the other side of the world right now. Kuso." He cursed, not believing that Boros would afford him the time to travel around the planet, however brief it may have been had he used the majority of his speed. An object soon appeared in his vision, displaced from it's resting place due to Boros' shockwave of energy a few moments ago. "Oh, A ship!"

Almost instantaneously reaching said formerly sunken ship, he placed Tatsumaki on the decaying deck. That would have to do for now, Boros' certainly wasn't a patient villain.

"HEY! What do you think you're doing, B-class!? This place is filthy and stinks!" Tatsumaki instantly took to complaining about the ship's condition, which she wasn't in the wrong to do. It looked like it had been sunk for centuries, so maintenance was obviously out of the questions for anyone not able to withstand the pressures of the deep sea or pull it out.

"… Just make one of those force-field thingies, I promise you'll be treated to something better when we get back." Pinching the bridge of his nose, Saitama disappeared, leaving Tatsumaki with those words. Due to her already delirious state, the fantasy episodes returned, which would keep her occupied for quite a bit. She unconsciously formed the force field, keeping all impurities away from her person.

 **-Ground Zero-**

"Meteoric Burst." Saitama reappeared, only to have Boros fist slam into his face, causing him to wince in slight pain and be sent flying back. The power packed into the punch, as well as the speed Boros was moving out, caused a myriad of things to happen, the least of which were a sonic boom and an explosion akin to a nuke. He followed Saitama's figure through the smoke, and proceeded to rapidly fire hits at him.

Saitama regained his posture midair, and fired back. It was a shame, really. If only mortals could perceive the hundreds of punches, kicks, and feints per second happening during this exchange, they could garner an appreciation for these powerful beings. Blow for blow. Adjustment to adjustment. **Power begetting power**.

The two split apart. Boros had lost an arm, while Saitama's face was marred with cuts and the top half of his costume had been completely blown off, revealing his chest (akin to Goku when facing a tough opponent).

Boros singular eye widened and became bloodshot. He had some semblance of a smile, since he didn't have a visible mouth in his meteoric burst form but Saitama had managed to make him cough up blood and force a grin to appear.

"This form takes an extreme toll on my body and shortens my lifespan, so I'll go all out here hero." Boros, revealing his one shortcoming, proceeded to regenerate his arm and produce a terrifyingly enormous aura. A storm had been conjured in response to his rising power, and lightning struck wildly across the horizon as waterspouts began to form near him.

Saitama, realizing that this was to be the final showdown, tightened his knuckles and adopted a serious expression. "In that case, I'm using my final move too." Lightning struck between the two, almost as if to signify the beginning of the end.

Exuding enormous amounts of energy, Boros pooled it all into a singular part in his body, his chest. As his heart is the core of his energy supply, he needed to gather all of his power and direct it there to have the maximum output.

Two heartbeats could be heard simultaneously, although they were of the exact same frequency. The combatants… they were enjoying themselves to the fullest.

"… Collapsing Star, ROARING CANNON!" Boros, his voice building up in decibels as he fired his ultimate attack, released a beam that could easily be the size of a country from his chest.

"This attack will destroy the planet if you don't stop it! Now, Saitama the hero, give my existence THE ULTIMATE STIMULATION!"

Saitama faced the beam, got into a stance, and swung his bare fist at the attack. "Serious series: Serious Punch!"

The attacks collided, with Saitama's plowing through Boros' just enough to smack him with the pressure from it. The beam was split in two, although Saitama got thrown back because of it and (conveniently) crashed extremely hard into the ship Tatsumaki was on, spitting up blood. This shook Tatsumaki from her daydreams, and she made to examine the situation.

 **-Tatsumaki POV-**

"What's going o- Oh my God! IS THE WORLD ENDING!? There's clouds and tornadoes made of water and lightning and… WOAH! Is that B-class?! He looks terrible! Not that he didn't already look bad but he's fucked up!"

She scrambled over to his side, panicking over the thought of having lost a perspective partner, and even more at probably having to deal with the media about it. Just then, he stirred.

(Back to narrator POV)

"Ugh, this guy sure can pack a punch." Saitama was able to get up to his feet, wobbling as they may be. He hadn't ever been this exhausted, not even back when he was an ordinary human with no job. He was sure he was going to be sore for weeks, not to mention the totaled costume and...

"I BROKE MY HAND!? WHAT IN THE…" He became instantly and gigantically annoyed as he examined his limp right hand, the same one he had used to punch the beam. It ached and stung and wouldn't move with his commands.

"I can't eat udon left-handed damnit! Noooooooooooooooooooooooo!" The Dominator of the Universe had dominated his foe once again, albeit in a different sense this time.

 **-Destroyed City A-**

Boros was now lying flat on his back, his lower body having been obliterated. He had been blown back to city A by Saitama's punch. Their battle had literally taken them back and forth across the planet it seems.

"… It's a very good thing I held back a small portion of my power." With a pained wheeze and enormous effort, he regenerated his lost lower half and his bodies color. Regaining his senses, he got up and started to survey the area.

"It appears that was next to the last of my energy. I will not be able to fight for some time, but where am I? Ah yes, this is the point of contact. I have lost my ship and all of my subordinates, so I can't return home. What's the best option here, I wonder?"

Wondering around the city he destroyed shakily, he came upon one of the still standing buildings that read "Heroes Association HQ." With a watered down version of his battle maniac grin, he hatched a plan.

"I've lost all my subordinates and all of my equipment… but that doesn't mean I can't get more from this place." Continuing on his stroll, he disappears into the darkness, biding his time for when he can face his rival at full power once more.

(Time-skip).

It's been about a week since the alien invasion. Saitama was flown back to Japan by Tatsumaki, whom continues to come by his house demanding that he "take responsibility" for reasons unknown to him. His broken hand hasn't fully healed, so Genos had taken it upon himself to feed him whatever meals they ordered, much to Saitama's chagrin. All of the heroes have returned to their normal lives, and City A is about a ¼ of the way to being completely revealed. Basically, it's the same old same old for the strongest hero: uneventful as hell.

"… I'm leaving, Genos! Be back when-the-fuck-ever!" He trailed off as he said the last part, though Genos' enhanced hearing allowed him to hear it anyway, prompting a "Hai, sensei!" in return. Saitama trudged through the door, closing it with his only good hand.

Walking nowhere in particular, the bald hero sighed. The supermarket sale was today, but he was flat out of cash at the moment, Genos wouldn't stop worrying about him, Tatsumaki was probably going to get him thrown in jail for seemingly "engaging" with a loli (even though she is 28), and to top it all off, he didn't even know where the hell his rival went or if he survived. Life currently sucked even harder than usual.

Just then, a tall, completely obscured man wearing a large trenchcoat and hat combo along with… pointed boots, passed by him.

 **-Saitama POV-**

"What is this strange aura I'm feeling? It almost feels like…" I turned and saw a large man passing by. I can't see any part of his body, but feel a very strange sense of familiarity about him. Eh, must just be a conincidence

(Narrator POV)

The strange, tall man stopped in an alley after clearing Saitama's hearing range. He spoke in a guttural voice, dictator like in his presence and posture.

"Since Saitama has amassed underlings in this 'Heroes Association', I may as well have done the same. Izuna, have you started the preparations?"

"Yes I have, Lord Boros-sama."

 **End! I'm on the fence on whether I should continue this, my original focus was just to make the battle scene between Saitama and Boros less of a let-down, but seeing as how this is my most liked story (47 favorites, you guys do know I thought this up while I was web-surfing on bing and found a "female" version of Boros right? Lol, thank you all!) I'm 60% sure I'll continue.**

 **Yes, I left both of them alive. Killing off Boros would've felt anti-climactic, as this is one of the few stories I can find him in, and Saitama's the MC so that's a given.**

 **Let me know in the reviews in you want me to keep going! I'll also be doing a Highschool DxD fic in a short timeframe, so take a look at that if you feel so inclined. Later Peeps!**


	5. Chapter 5

**Chapter 5: Those In the Shadows**

"Damnit, one punch again". A stream of monsters lay dead in a deserted part of city A. The culprit? Not a bald headed, hero-for-hire, but a tall, well-built cyclops with little patience left to give.

"I'm not going to get anywhere questioning these weaklings. Izuna!" The tall alien man called out the name of his servant, even though he or she was nowhere in sight. A faint cracking noise was heard, and then, suddenly a plant sprouted on the spot.

"Yes, Lord Boros?" This creature looked fierce, being akin to a venus fly-trap in form, but spoke in a meek and fearful tone when around Boros. "You called?"

"I thought you said that these lower level minions would revere the higher-ups of the Heroes Association. Thus far, I have come across none that even know of the name "Saitama". Was your information incorrect?" Boros' single eye turned bloodshot, and electricity began crackling around his body. Izuna retreated into a fetal position (as close to one as a plant can get, anyway) and cowered.

"No sir, I heard it from the heroes themselves!"

"WHAT heroes, Izuna?" Boros' aura grew even more frightening.

"Eep! T-they were called B-rank heroes, I think! There's 4 ranks of heroes and they are the second lowest!"

Boros calmed down, quelling his static in his aura and adopting an expression of thoughtfulness. An insane smile crossed his lips, just as in his fight with Saitama.

"Well, let's hope they can provide more of a challenge and more info than these fodder monsters here. I'm not 100% yet, but this planet is full of pitiful fighters. It's time to start a hero-hunt." With those words, he moved at obscene levels of speed, seemingly vanishing into thin air. His servant followed suit, retracting into the ground from whence it came. Shortly after they departed, a batch of heroes arrived on the scene, the most noticeable among them being a cyborg.

"Hey Genos, over here! I found the monsters!" A rather ordinary-looking hero called out. Genos, having been appointed leader of this mission, strolled over to the scene of the genocide.

"… These were supposed to be demon level monsters, and yet, they're all dead, and there's barely any traces of a struggle. In fact, it looks like they were defeated with minimal effort on the attacker's part. If I didn't know any better, I'd say this was the work of master, the work of-

 **(scene change, Apartment Complex)**

"Baldy!" Tatsumaki yelled out Saitama's official hero name, banging on the door to his apartment, much to his chagrin. It had been 3 months since the God-level threat that Boros posed was put down, and Saitama had continued on in his mundane hero duties. His hand had healed, but his boredom (and irritation) had not. The city had been rebuilt, so there's that, but Saitama's existential crisis remained.

"Open up, baldy!" Another infuriating set of knocks at the door.

"You know, that's not the way to talk to someone who's house you're trying to enter! Why don't you try being nice for once!?"

Tatsumaki, irritated at having to wait so long and disregarding Saitama's suggestion, ripped the door off it's hinges with her telekinetic powers and threw it into orbit. Surprisingly, Saitama didn't freak out like many would have expected him to. Instead, he just sighed and motioned for her to come in, since he knew there wasn't any other choice to be had in reality.

"That's the third one in the last two weeks, my poor hero salary." He lamented his situation, having to constantly pay for destroyed or misplaced doors, all because of a girl who, while not bad to look at, had the worst attitude problem this side of the galaxy. "The least you could do is introduce me to the person that was out there with you." He made note of the taller, more mature woman that still stood outside.

"Grr, fine, only if you promise to take responsibility!"

"What does that even mean, you loli!"

"I'm pretty sure it means that she's-" the woman standing outside spoke up for the first time.

"Shut it, Fubuki! What would you know of how I feel!?" At this, the now-named Fubuki came inside, shedding anime tears at Tatsumaki's exclamation and sitting down beside her.

"You're right, I'm just a 20 something who's never had a boyfriend or even been asked out!" Fubuki sobbed and sneezed on a tissue she produced out of thin air.

"So, uh about that introduction…" Saitama was bewildered, but a guest is a guest and he didn't want to be rude.

Tatsumaki obliged. "Oh right, baldy this is my younger sister Fubuki."

Saitama's eyes bulged out of his head.  
"Younger!?"

"Yes, younger, octopus. Is that so hard to believe?" Tatsumaki's green aura flared up, shaking Saitama's entire apartment complex.

"Okay, stop, I believe you! I'll even do that 'take responsibility' thing, just don't destroy my house again!"

"Good! Now, let's get down to why we came here." Tatsumaki's aura settled down, and she sported a smile that was to die for. Turning on the tv and the console, she placed a controller in both the hands of her companions. "Let's play some DOOM! RIP AND TEAR TIME!" Her smile suddenly evaporated, turning into a maniacal grin filled with sadistic glee.

"They could at least bump me up to A rank if they're going to make me deal with this loli. Her sister, on the other hand, is nice and quiet. Wouldn't have expected that, someone related to the loli to be normal. Wonder what she's thinking right now? Probably normal stuff." Saitama whispered to himself.

"My sister is such a brute, and this man is giving me the creeps, staring at me like that. Is he really this awe-inspiring savior that she made him out to be before we came here?" Fubuki silently questioned the validity of Saitama's power (and her sister's sanity). She could do nothing but sit mute against these two domineering personalities.

 **-5 hours later-**

The telekinetic twins were all set to leave Saitama's mildly damaged home, having gotten their fill (well, Tatsumaki got her fill) of violence and bloodshed. They completed the entire game, from start to finish, and only the coming of nightfall had stopped Tatsumaki from starting a new game.

"See ya, kneecap! I guess it was kinda fun today!" Tatsumaki waved lazily, floating out of the hole where his door used to be. Fubuki stuck to walking, following closely behind her eccentric sister. Saitama sat there, bemoaning the loss of his door (again). After they were out of sight, he postured to himself.

"Well, it's nice to have ladies over from time to time I guess. There's only so much Genos I can take before I start wanting to see the other side of the species, even if it is an irritating loli."

The sisters walked on until they got to a fork in the road.

"Guess I'll see you tomorrow… or not, I don't really know." Tatsumaki made a half-baked attempt at a goodbye.

"Guess I'll see you whenever as well." Fubuki followed suit, not putting much heart into the brief conversation. The sisters were estranged, it seemed, and seldom did they ever both go out like this. Fubuki only agreed because she got a kick out of her sister not acting so high and mighty, which always seemed to be the case around this 'Saitama' guy (why was he named after a prefecture anyway?)

With that, the sisters split off and returned to their routine lives. Fubuki, being the highest ranked B hero and nicknamed the "Blizzard of Hell", had her own base and band of followers. She couldn't wait to get back to her home and embrace her underlings, they were like family to her almost. Fate is cruel sometimes.

 **(Blizzard Group HQ)**

Fubuki dropped her purse that she was carrying. Her men… every single one of them. They lay there before her, sprawled out on the ground and barely breathing. Standing over them, with a foot on the throat of a grunt, was a tall man with a body that glowed blue and purple. His hair was spiky, and he only had one eye.

"Tell me, weakling, do YOU know who Saitama is? You're a B rank hero, yes?"

"I-I don't know who you're talking about! P-please, spare us!" The nameless grunt pleaded for his life, looking at Fubuki out of the corner of his eye. Boros, unamused, simply picked him up and flung him against the wall with one arm before turning around and spotting Fubuki.

"W-who are you? Why do this to my men!?" Fubuki was terrified, but also incensed that her squad had been so thoroughly devastated, seemingly from just this one monster. "And did you say Saitama?"

Boros rushed forward, his eye wide and his manic smile present. He grabbed Fubuki by the throat, slamming her against an adjacent wall and knocking the wind out of her. She had tried to conjure up one of her techniques, but Boros was too fast. He spoke with a sense of fulfillment.

"At last, someone that knows of him."


End file.
